Hot tub cover size
Four numbers define your hot tub cover size: outside length, width, corner radius, and skirt length. Round both length and width up to the nearest inch. Round down when measuring the corner radius.
- An oversize of 2.5 to 5 cm still fits right.
- 1 to 2 in
- 1.9 cm of build tolerance, either way
- 0.75 in
- Square corner radius
- 0 in
- Center thickness (10 to 15 cm), light to heavy duty
- 4 to 6 in
How to measure hot tub cover size
According to Spa Depot's measuring guide, measure the old cover if it fits well and has not warped. Measure the tub shell if the old one sags, is warped, or is gone. Gather a pen, a carpenter square, and a tape measure.
- Width and length come next. Find the widest outer edge on the shell or cover and measure it. For each number, round up so you land on the next whole inch. A small difference, such as 84 by 85 in, usually points to a square tub.
- Next check the corner radius. Place a carpenter square against the corner. See where the curve hits the inch marks to find the radius. Round down because a smaller radius works with a larger curve.
- The skirt measurement follows. Start at the cover seam and measure down, or use the bare shell lip plus around 0.5 in (1.3 cm). Round upward to the next inch. Below the skirt, straps hang about 4 in (10 cm).
- Folding comes last. The length folds in half at the center hinge. Rectangles usually fold on the long side, keeping the keypad clear.
Round tubs require just one figure: the outside diameter rounded up. Spa Depot makes round covers only for perfect circles, never ovals. Measure from the curve center on each cut corner of an 8 sided tub, then round down.
Hot tub cover size chart by model
Manufacturers list these outside dimensions. Measure your tub before ordering because custom covers match your numbers.
| Tub | Outside size | Corner radius |
|---|---|---|
 Jacuzzi J-335, J-345 | 84 x 84 in (213.5 cm) | About 11.1 in (28.3 cm) |
| Jacuzzi J-355, J-365 | 84 x 91 in (213.5 x 231 cm) | About 11.1 in (28.3 cm) |
| Jacuzzi J-375, J-385 | 91 x 91 in (231 cm) | About 11.1 in (28.3 cm) |
| Jacuzzi J-235, J-245 | 84 x 84 in (213.5 cm) | About 8 in (20.3 cm) |
| Jacuzzi J-275, J-280 | 90 x 90 in (228.6 cm) | About 8 in (20.3 cm) |
| Jacuzzi J-215 | 66 x 76 in (168 x 193 cm) | About 8 in (20.3 cm) |
 Hot Spring Jetsetter | 84 x 68 in (213 x 173 cm) | Not listed |
| Hot Spring Vanguard | 87 x 87 in (221 cm) | Not listed |
| Hot Spring Grandee | 100 x 91 in (254 x 231 cm) | Not listed |
 Bullfrog A8 | 94 x 94 in (239 cm) | Not listed |
 Master Spas TS 8.2, TS 8.25 | 94 x 94 in (239 cm) | Not listed |
| Master Spas TS 7.2, TS 7.25 | 84 x 84 in (213 cm) | Not listed |
| Master Spas TS 6.2, TS 240X | 78 x 78 in (198 cm) | Not listed |
| Master Spas TS 67.25 | 70 x 84 in (178 x 213 cm) | Not listed |
The radius for Jacuzzi comes from its spec handbook and applies to the cabinet corner. Since the cover rests on the shell rim, verify yours with a carpenter square.
Thickness and taper of the cover
The taper is the slope from the thicker center to the edge of a spa cover. Spa Depot's DuraTherm covers offer three grades.
| Grade | Center | Edge | Made for |
|---|---|---|---|
| Light duty | 4 in (10 cm) | 2.5 in (6.4 cm) | Indoor spas |
| Standard duty | 5 in (12.7 cm) | 3 in (7.6 cm) | Better than a factory cover |
| Heavy duty | 6 in (15 cm) | 4 in (10 cm) | Most energy savings |
Spa Depot notes that extra foam improves insulation. A snug, thick cover also helps bring down the running cost of a tub outdoors.
Common questions
Is a hot tub cover supposed to be bigger than the tub?
Just a little. Covers that are 1 to 2 in (2.5 to 5 cm) oversize usually fit well, according to Spa Depot, but ones that are too small don't. This is why you round up the width and length.
Do you measure the hot tub or the old cover?
Use the old cover for measurements if it fits well and has not warped. Measure the widest outer shell edge if the cover sags, warps, or is gone.
How do I find the corner radius of a hot tub?
Place a carpenter square against the corner. Look for where the curve touches the inch marks on the tool arms to find the radius. Round this number down because a smaller radius matches a larger curve.
What length should the hot tub cover skirt be?
It needs to be long enough to cover the lip of the shell. The bare lip is what you measure; add roughly half an inch (1.3 cm), then round upward to the next whole inch.